Area Forecast Discussion
Issued by NWS Charleston, WV

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000
FXUS61 KRLX 260812
AFDRLX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHARLESTON WV
412 AM EDT SAT JUL 26 2014

.SYNOPSIS...
UPPER LEVEL LOW WITH DISTURBANCES IN THE FLOW THROUGH TONIGHT.
COLD FRONT WITH STRONG STORMS SUNDAY. LINGERING CONVECTION IN THE
UPPER LEVEL LOW THROUGH MONDAY. COOLER AIRMASS SETTLES IN PLACE
THROUGH MID WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
MODELS ARE IN GOOD AGREEMENT ON A VIGOROUS SHORT WAVE APPROACHING
FROM THE WEST TONIGHT...WITH A WELL DEFINED WARM FRONT FOR THIS TIME
OF YEAR LIFTING NORTH AND EAST TOWARD OUR AREA. GIVEN THE STRENGTH
OF THE DYNAMICS AND A MODERATE 850 MB SOUTHWESTERLY JET FEEDING WARM
AND QUITE MOIST AIR NORTHWARD...THE MODELS TARGET THE BEST
COMBINATION OF THESE PARAMETERS RIGHT ACROSS OUR AREA...MAINLY
LATER TONIGHT IN THE FORM OF AN MCS. WITH HPC AND SPC ALSO TARGETING
OUR AREA WITH A RISK FOR BOTH SEVERE STORMS AND EXCESSIVE
RAINFALL...HAVE TO GO WITH THIS SCENARIO. THIS BRINGS CAT POPS FROM
THE WEST AND NORTHWEST ACROSS OUR AREA TONIGHT...AGAIN MAINLY AFTER
MIDNIGHT. HOWEVER...OF SOME CONCERN IS THE EFFECTS OF A STILL
NORTHWESTERLY COMPONENT OF THE 1000-5000 MB THICKNESS FIELDS...WHICH
MAY PULL THE ANTICIPATED COMPLEX FORMING WELL UPSTREAM LATER TODAY
MORE SOUTHEASTWARD INTO KENTUCKY. AT THIS POINT THOUGH...FROM ALL
THAT IS MENTIONED ABOVE...CONFIDENCE IS NOT HIGH ENOUGH TO DEVIATE
FROM GUIDANCE. WILL MENTION THESE CONCERNS IN THE HAZARDOUS WEATHER
PRODUCT FOR NOW...UNTIL WE GET MORE CONFIDENCE IN THE EVOLUTION OF
THINGS TODAY BEFORE ANY WATCHES ARE CONSIDERED.

OH YES...ABOUT TODAY. TODAY WILL BE THE TRANSITION TO THE SETUP FOR
TONIGHT. SURFACE HIGH PRESSURE SHIFTING FARTHER OFF TO THE EAST WILL
ALLOW STRONG WARM AND MOIST ADVECTION ON INCREASING SOUTHWESTERLY
FLOW. EARLY MORNING UPPER DISTURBANCE WITH THE WIDESPREAD MID CLOUDS
WILL LIFT OUT BY MID MORNING...BEING REPLACED BY A SCATTERED CU
FIELD THIS AFTERNOON WITH LACK OF UPPER DISTURBANCES. THUS...KEEPING
THINGS DRY BUT MUCH WARMER AND MORE HUMID TODAY UNDER A GOOD DEAL OF
SUNSHINE. GOING ON THE WARMER SIDE OF GUIDANCE WITH HIGHS
APPROACHING 90 DEGREES.

&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
BEST PLACE TO START WITH THIS FORECAST IS THE MODERATE RISK FROM SPC
IN THE MIDDLE OHIO VALLEY AND CENTRAL APPALACHIANS FOR SUNDAY INTO
SUNDAY NIGHT. ALSO HAVE THE POTENTIAL FOR EXCESSIVE RAINFALL.

UPPER LEVEL LOW WILL DIVE INTO TH GREAT LAKES FROM THE NORTHERN
PLAINS LATE THIS WEEKEND WITH YET ANOTHER DYNAMIC SYSTEM. WILL
LIKELY BE DEALING WITH A LATE NIGHT MCS  TOWARDS THE BEGINNING OF
THE SHORT TERM FORECAST BRINGING A WIND THREAT. THIS COULD WORK TO
DESTABILIZE THE ATMOSPHERE LATER IN THE DAY WITH COOLING TO THE MID
LEVELS AS THE SURFACE RECOVERS UNDER SOLAR INSOLATION...THUS
INCREASING THE LOW AND MID LEVEL LAPSE RATES INTO THE LATE AFTERNOON
AND EVENING SUNDAY. STORMS WILL FORM ALONG THE STRONG COLD FRONT AND
PROPAGATE RAPIDLY WITH AN OBVIOUS WIND THREAT AS WELL AS LARGE HAIL.
AS THE SPEED SHEAR INCREASES WITH THE APPROACHING OF THE UPPER LEVEL
LOW...SO DOES THE DIRECTIONAL SHEAR OVER THE LOW LEVELS...AND WILL
SEE SOME VEERING WITH HEIGHT.

RAPID DRYING ALOFT ABOVE 700MB OCCURS AFTER 00Z MONDAY...BUT AS THE
UPPER LOW ROTATES INTO LAKE ERIE...ANOTHER AXIS OF MOISTURE WILL
DROP IN FROM THE NORTH. THIS KEEPS THE POPS GOING AFTER A SHORT
REPRIEVE INTO THE MONDAY TIME FRAME.

IN THE END...THIS COLD FRONTAL PASSAGE WILL BRING YET ANOTHER
SIGNIFICANT CHANGE IN AIRMASS...IN A JULY THAT HAS SEEN A STEADY
DOSE OF THESE COLD FRONTS THAT HAVE USHERED IN INFLUENCES FROM
CANADIAN HIGH PRESSURE. MAX TEMPERATURES WILL BE BACK DOWN AROUND 10
TO 15 DEGREES BELOW NORMAL.

&&

.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
HIGH PRESSURE BEHIND THE COLD FRONT TAKES CONTROL LATER MONDAY NIGHT
THROUGH THE MIDDLE OF NEXT WEEK WITH NEAR NORMAL TEMPERATURES.

BLENDED HPC WITH PREVIOUS FORECAST NUMBERS AS THEY LOOK
REPRESENTATIVE UNDER HIGH PRESSURE AND SLIGHTLY COOLER NORTHERLY
FLOW.

&&

.AVIATION /08Z SATURDAY THROUGH WEDNESDAY/...
06Z SATURDAY THRU 06Z SUNDAY...
UPPER LEVEL DISTURBANCE OVERNIGHT WILL CONTINUE VFR CEILINGS AOA
8000 FEET. THIS WILL LIMIT FOG TO SCATTERED MVFR RIVER AND VALLEY
FOG 08Z TO 12Z. AFTER 12Z...BECOMING SCATTERED CU WITH HEATING AS
UPPER DISTURBANCE LIFTS OUT.

THUNDERSTORM COMPLEX WILL BEGIN TO AFFECT AREA AFTER 03Z FROM THE
NORTHWEST...AND MAY REACH JUST PAST OHIO RIVER AROUND 06Z. GREAT
UNCERTAINTY ABOUT THE DEVELOPMENT AND TRACK OF THIS EXPECTED COMPLEX
ALONG WITH THE LATENESS OF THE POTENTIAL EVENT...LEADS A TAF
FORECAST TO BRING MVFR CONDITIONS WITH SHOWERS AND SCATTERED STORMS
TO PKB ONLY AND JUST SHY OF HTS BY 06Z. THE REMAINDER OF THE TERMINAL
SHOULD REMAIN PRECIP FREE THRU 06Z.

FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 06Z SUNDAY...

FORECAST CONFIDENCE: HIGH TODAY...LOW TONIGHT.

ALTERNATE SCENARIOS: TIMING...COVERAGE AND DENSITY OF FOG OVERNIGHT
COULD VARY DEPENDING ON CLOUD COVER. THUNDERSTORM COMPLEX OVER AREA
SATURDAY NIGHT IS UNCERTAIN.

EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH:   TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW:    TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.

DATE                    SAT 07/26/14
UTC 1HRLY       08   09   10   11   12   13   14   15   16   17   18   19
EDT 1HRLY       04   05   06   07   08   09   10   11   12   13   14   15
CRW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
HTS CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
BKW CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
EKN CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
PKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H
CKB CONSISTENCY  H    H    H    H    H    H    H    H    H    H    H    H

AFTER 06Z SUNDAY...
IFR POSSIBLE IN ROUNDS OF CONVECTION SATURDAY NIGHT INTO SUNDAY
NIGHT.

&&

.RLX WATCHES/WARNINGS/ADVISORIES...
WV...NONE.
OH...NONE.
KY...NONE.
VA...NONE.

&&

$$
SYNOPSIS...JMV/26
NEAR TERM...JMV
SHORT TERM...26
LONG TERM...ARJ
AVIATION...JMV








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